1. Field of the Invention
This invention relates to hoists, winches, and other pulling and/or lifting devices.
2. Background of the Invention
Hoists and winches are used extensively to lift, lower, or pull loads of various kinds Such devices typically include a line, such as a cable or chain, wrapped around a spool. To lift, lower, or pull a load, the spool may be manually rotated or driven with a motor, such as an electrical, hydraulic, or pneumatic motor. When rotation is not desired, a braking mechanism may be used to prevent the spool from turning. This may maintain tension in the line, keep a load suspended, or prevent the release or unspooling of the line. To keep the line from bunching on the spool, some hoists or winches may include guides or other mechanisms to evenly wind the line around the spool.
Although a wide variety of hoists and winches are available, many have shortcomings that prevent or discourage their use in various applications. For example, some hoists or winches are bulky or cumbersome, which may prevent their use in applications where greater compactness is required or desired. Other hoists and winches may be economically infeasible for use in applications such as consumer or residential applications due to their complexity or expense.
The accuracy and precision of some hoists and winches may also be lacking in certain applications. For example, because the line of a hoist or winch may be wound around itself in an irregular or unpredictable manner, the effective diameter of the spool may change for line that is drawn in or let out from the spool. The result is that, for any given angle of rotation of the spool, an unpredictable amount of line may be drawn in or let out. This can make the hoist or winch unsuitable for applications where a high degree of precision is required. It can also make the winch or hoist unsuitable for operations that require a high degree of repeatability.
Some hoists and winches may also have shortcomings in terms of the control and information they provide. For example, current hoists and winches may lack mechanisms for determining certain parameters during operation. For example, short of manually measuring or observing a hoist or winch, it may be difficult or impossible to determine how much line is let out from the hoist or winch at any given time. Even if possible, it may not be possible to do so with a desired degree of precision. In other cases, the ability to determine a load on the hoist or winch, or adjust the speed of a hoist or winch (which may depend on the load) may be lacking. In yet other cases, an event such as a power outage or reset may cause a hoist or winch to forget or lose information regarding current operating parameters.
As with most fields of endeavor, improvements are constantly sought after by those of skill in the art. As it relates to hoists and winches, improvements are needed to address bulkiness, complexity, expense, precision, and control, as discussed herein. Ideally, such improvements will create new applications for hoists or winches, or make hoists or winches more economically or practically feasible for existing applications.